Fluid engine

ABSTRACT

A pressurized fluid engine comprising a rotor rotatable about a central axis of rotation and within a casing, the rotor having a hollow interior bounded on substantially its entire inner periphery by at least one inclined surface substantially parallel to and facing the axis having a leading end with respect to the direction of rotation closer to the axis than its trailing end in order that outward fluid pressure on the surface or surfaces exerts a mechanical leverage inducing the rotation. The fluid on the interior of the rotor after applying this pressure on the inclined surfaces escapes freely through an exit that is substantially free of any fluid compressing flow restrictions.

United States Patent Theis, Jr. et al. 1451 Dec. 26, 11172 54 FLUID ENGINE 2,111,136 3/1938 Bauer ..41s/s1 2,165,808 7/1939 Murphy.... .416/186 [72] Inventors. James V. Theis, Jr., Park Forest,

Jo n B. Mccord Evanston; Harry 2,767,906 10/1956 Doyle ..4l6/186 H. Holly, Olympia Fields, all of 111. FOREIGN PATENTS OR APPLICATIONS [73] Assignee: Hollymatic Corporation 286,171 7/1915 Germany ..4l5/206 [22] Flled: 1970 Primary Examiner-Henry F. Raduazo [21] Appl. No.: 93,288 Attorney-Hofgren, Wegner, Allen, Stellman & Mc-

Cord

[52] US. Cl. ..416/l86, 415/503, 44115571214, [57] ABSTRACT [51] Int. Cl ..B63h 1/16, FOld 3/00, F04d 7/00 A pressurized fluid engine comprising a rotor rotata- [58] Field of Search ..4l6/ 176-186, 203; ble about a central axis of rotation and within a cas- 4l5/204-206,71-86, 503,211 ing, the rotor having a hollowinterior bounded onsubstantially its entire inner periphery by at least one [56] References Cited inclined surface substantially parallel to and facing the axis having a leading end with respect to the direction UNITED STATES PATENTS of rotation closer to the axis than its trailing end in 4 750 2/1872 Kelly order that outward fluid pressure on the surface or 24539397 5/1953 Framer surfaces exerts a mechanical leverage inducing the 2,652,190 911953 M m 1, rotation. The fluid on the interior of the rotor after ap- 2,857,094 10/1958 Erwin plying this pressure on the inclined surfaces escapes 3,095,821 7/1963 Elenbaas freely through an exit that is substantially free of any 762,175 6/1904 Lees fluid compressing flow restrictions. 933,681 9/1909 Valk 1,062,803 5/1913 Simond ..41 5/71 3 Claims, 4 Drawing Figures PATENTEDBEBZB w a. 707; 336

N In 7% FIGZ INVENTORS.

JAMES v. THEIS.JR.

JOHN, B. McCORD HARRY H.HOLLY BY WW g .41 JM 547m ATTORNEYS.

FLUID ENGINE FIELD OF THE INVENTION One of the features of this invention is to provide a fluid pressure engine or motor including a hollow rotor with an annular inner side wall or periphery defined by at least one inclined surface against which the fluidized pressure bears, before escaping through an exit, to rotate the rotor.

Another and more specific feature of the invention is to provide such an engine in which this inner periphery comprises a pair of the inclined surfaces each extending about 180 and each curved substantially to a spiral whose center is at the axis of rotation of the rotor with the surface increasing in radius from the leading edge of this surface toward the exit for the fluid.

Other features and advantages of the invention will be apparent from the following description of the embodiment thereof illustrated, described and claimed herein.

The most pertinent prior art of which applicants are aware are U. S. Pat. Nos. 37,841 and 3,468,385. Each of these, however, differs from the invention here as each exit nozzles including fluid compressing flow restrictions in that these exit nozzles are converging and thereby fluid constricting and have the effect of compressing the fluid during its passage from the rotor, thereby reducing the energy of the pressurized fluid flowing in and through the rotor. Another prior art patent is U.S. Pat. No. 2,639,897 and this differs from the invention here principally in that this prior art patent discloses a rotor having curved interior surfaces facing the axis of rotation but these are not inclined as required in the present invention but are of uniform radius and thus coaxial with the axis of rotation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged longitudinal axial sectional view through an air motor or engine embodying the invention with this embodiment being shown at about double actual size.

FIG. 2 is a partial sectional view through the rotor of the engine taken substantially on a vertical diameter of FIG. 1 substantially along line 2-2.

FIG. 3 is an end elevational view'of the rotor of FIG. 2 but with the end removed with the result that the view is taken substantially along line 3-3 of FIG. 2.

FIG. 4 is a rear elevational view of the engine casing illustrating the large plurality of exhaust passages in this embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the embodiment shown in the drawings the fluid motor or engine is supplied with pressurized fluid,

here supplied with compressed air through an air tube 1 1 which communicates with the interior of the casing 12. Coaxially located within the casing 12 is a rotatable shaft 13 held at its forward end by a ball bearing 14 and at its rear end by a ball bearing 15.

Rearwardly of the ball bearing 15 the casing 12 is enlarged in diameter to provide a circular chamber 16 that is substantially coaxial with the shaft 13. Mounted on this shaft rearwardly of the bearing 15 and within the chamber is a rotor 17 that is itself coaxial with the shaft 13, the casing 12 and the chamber 16.

The rotor 17 has a hollow interior 18 defined by side walls substantially at right angles to the central axis of rotation 21 as shown in the drawings and a peripheral wall in two sections 19 and 20. The hollow rotor is thus of low mass as shown in the drawings. The two wall sections 19 and 20 lie along a circle whose center coincides with the central axis of rotation 21 of the shaft 13 and rotor 17. As can be seen in FIG. 3, the two sections 19 and 20 have their ends spaced apart to provide a pair of fluid exits 22 and 23 comprising exit nozzle means of short length, as shown most clearly in FIG. 3,

from which the fluid flowing through the hollow interior 18 exits with low frictional drag essentially tangentially to the circle defined by the wall sections 19 and 20 as indicated by the arrows 24. Thus the hollow interior 18 of the rotor is bounded by the side walls, or, as shown, front 56 and rear 37 walls.

Positioned on the inner side of the wall section 19 and of less height is a wall member 25 which operates as a fluid confiningwall having an arcuate surface 26 sloped rearwardly and outwardly from a leading end 27 to a trailing end 28 that defines the outer extremity of the exit 23. The surface 26 and the similar surface 31 on the opposite similar wall 30 are transversely flat as can be seen in FIG. 2 in connection with surface 26. As shown in the drawings, the wall member 25 and 30 of the wall sections 19 and 23 comprise a peripheral wall that is substantially concentric with the axis of rotation 21. The trailing end 28 is located further from the axis 21 than is the leading end with the result that fluid pressure in the hollow interior 18 of the rotor 17 presses outwardly against the inclined surfaces 26 and 31 to exert a mechanical leverage of the rotor 17 and thus shaft 13 and rotate them in the direction illustrated by the arrow 29 in FIG. 3.

In the preferred construction as shown in the drawings the curved or expanding surface 26 lies at least approximately along a spiral which in the illustrated embodiment in an Archimedean spiral whose center is located substantially at the axis of rotation 21.

Located diametrically opposite the wall member 25 is a similar wall member 30 that is a mirror image of the wall member 25 and that also has an arcuate surface 31 like the surface 26, a leading end 32 and a trailing end 33 at the exit 22. As can be seen from FIG. 3 the leading ends, trailing ends and arcuate surfaces of the two wall members are diametrically opposite each other.

For proper balance it is preferred that no less than two fluid confining wall members 25 and 30 be used in order to aid in balancing the rotational forces of the rotor. Where two or more are used these should be symmetrically located around the rotor so as to have an additive effect in developing rotational force 29 when the fluid pressure bears against the arcuate surfaces as indicated by the fluid flow arrows 34a in FIG. 3.

In order to obtain the most efficient operation the leading ends 27 and 32 of the wall members 25 and 30 are shaped substantially as the leading edges of airfoils. This means that as the rotor 17 rotates in the clockwise direction 29 of the illustrated embodiment these ends move through the fluid on the interior of the rotor 17 with the least resistance to turning. In fact, by providing the leading edge airfoil curvature the resistance is even less than it would be if these edges were knife edges.

The hollow rotor 17 as is evident from the above has a central opening 40 in one 56 of its walls and the inner chamber 18 is smooth and vaneless and is located adjacent the central opening 40. The wall members 25 and 30 comprise a peripherally circular wall having an outer vaned impelling portion adjacent the surfaces 26 and 31 for the rotor with each of the vanes 25 and 30 including the inner surfaces 26 and 31 spiraling smoothly, arcuately outwardly and comprising airfoil sections, with the term airfoil being used broadly to mean a surface designed to obtain reaction upon its surfaces from a pressure fluid as defined herein.

Each smooth spiraling surface 26 and 31 terminates in a trailing end as shown at 28 lying in the peripheral circular wall 19-20. The adjacent vanes 25 and 30 have cooperating relationship as seen especially in FIG. 3 and define tangential substantially unrestricted discharge nozzles 22 and 23 the'rebetween. Each vane 25 and extends substantially 180 about the axis 21. Each vane 25 and 30 has a substantially rounded leading edge. This means that each leading edge is so shaped as not to constitute a substantial obstacle to, or retarder of, flow of the fluid relative to therespective leading edge 27 and 32. I

In operation, the fluid such as air under pressure in the illustrated embodiment flows through the tube 11 and into and through the air conduit or passage which is located in the rear end cover 36 substantially coaxially with the axis of rotation. This air passage 35 supplies air to the entrance opening to the hollow interior 18 of the rotor. As shown the air enters the entrance 40 coaxially with the axis of rotation 21 and then fans out through an angle of 90 to be directed outwardly at substantially right angles to the axis 21 and against the wall surfaces 26 and 31 to exert the rotational mechanical leverage as described. In order to aid this directing air the rear end of the shaft 13 extends through the rotor forward wall 37 so that the rear surface or end 38 is conically concave as a continuation of the curvature of the inner surface 41 of the interior 18 of the rotor.

Also as shown in the drawings, and particularly at FIGS. 2 and 4, the rotor opening 40 is at least as large as the conduit opening 35 (in this embodiment larger) so as to provide free flow of fluid to the interior of the rotor.

The rotor 17 itself is preferably made of a plastic material such as rigid nylon which further reduces its mass. The metal end 38 of the shaft 13 therefore forms a hard surface against which any solid particles in the fluid stream impinge.

The large entrance 40 to the rotor in conjunction with the adjacent projecting means 38 ,forming the expanding fluid passage 18 (FIG. 2) adjacent the axis 21 for converting axial 42 flow smoothly to radial 34a flow toward the air or fluid foil surfaces 26 and 31 comprise projecting means defining a surface for turning the flow smoothly from the axial 42 to the radial 34a direction in the vaneless portion of the rotor to enter the vaned portion with a radial component.

The air flowing into the rotor 17 as indicated by the arrow 42 in FIG. 1 is thereby turned at right angles as described and after impinging on the inclined surfaces 26 and 31 flows along these surfaces and is expelled from the nozzle exits as indicated by the arrows 24 in FIG. 3.

In order to aid in attaching and removing tools the embodiment of F IG. 1 has opposite sides of the shaft 13 flattened as indicated at 43 and the casing is provided with a slot 44 through which a tool may be inserted for engaging the area 43 and thereby holding the shaft 13 against rotation.

Any pressurized fluid may be used in operating the engine of this invention, either gaseous or liquid or, for that matter, gaseous combustion products such as produced from an explosive fuel-air mixture.

In the illustrated embodiment there are provided a pair of the inclined surfaces 26 and 31 which operate as inclined surfaces to exert mechanical leverage when subjected to the radially expanding fluid illustrated by the arrows 34a. There may be either one-or as many as desired of such inclined surfaces so long as their total extent encompasses substantially the entire periphery of the hollow interior 18. By this it is meant that the inclined surfaces should for best results extend at least 90 percent of the entire inner circumference of the retor.

The pair of diametrically located exits 22 and 23 in the illustrated embodiment are substantially free of any fluid compressing flow restrictions, that is, side walls 45 and 46 as well as the other boundary walls of each exit would not compress the escaping fluid in order that the passage of the fluid through the exits 22 and 23 will not impart energy to this fluid.

The importance of arranging the total inclined surfaces illustrated at 26 and 31 to extend substantially around the entire circumference of the interior 18 of the rotor has been proven by test results. Thus, where the total of these surfaces extends only 240, for example, the revolutions per minute at a given pressure with air as the fluid was about l00,000 rpm. Where the total inclined surfaces was for the full 360 the revolutions per minute was raised to 140,000 under the same conditions of dimensions of the engine, air pressure and the like. Even more startling, however, is the fact that these tests show that the torque by increasing this arcuate area from 240 to 360 was increased by over percent.

The fluid motor of this invention particularly when used as a hand held device to power a grinder or the like has a number of very important advantages and among these are included the following. Themotor has a very low mass and light weight, primarily because of the small number of parts and the preferred use of a combination of aluminum casing, steel shaft and rigid plastic rotor. As can be seen in the description of the preferred embodiment as shown in the drawings these constitute substantially all of the parts of the motor.

A further advantage is that the air exhaust from the rotor 17 even when operating at high speeds such as l40,000 rpm or more is silent. This is achieved by caus ing the air from the rotating rotor to flow radially outwardly into the chamber 16 at the areas of maximum internal circumference. This exhaust air indicated at 35a then reverses flow and finally flows rearwardly as shown at 45a through the large number of exhaust v openings 34 and 47 which together have a large total exhaust area.

A further important advantage is that the air exhaust flowing axially rearwardly as indicated by the arrows 45a is directed away from the hand of the operator grasping the device at the handle 48 and also away from the clothing of the operator and from the work itself which is at the front or left end of the driven shaft 13. This means that not only is the operator out of contact with the exhaust air but also that dust and fine particles from the work are not blasted into the air.

Another advantage is that the alignment of the driven shaft 13 and the motion imparting rotor 17 is easily achieved and is maintained constant throughout the life of the engine or motor.

Another important advantage is that the fluid reaction rotor is located at the rear of the device so that the handle part 48 is of small diameter and thus easily grasped by the operator. This not only aids in holding the device when operating at high speed but also permits the operator to maneuver the device easily and precisely. This also gives a secure grasp of the device by the operator because in use the enlarged chamber containing the rotor rests against the edge of the palm opposite the thumb of the operator.

In a specific embodiment only about 1 percent by volume of the air was diverted for forward flow as indicated by the arrows 49 for cooling the bearings 14 and 15. The other 99 percent was directed rearwardly as explained above. As a result of the construction features of this air motor it attains a speed of 140,000 rpm and higher in l or 2 seconds at an air pressure of 70-80 pounds per square inch. Even at these speeds there is substantially no vibration in the hand of the operator.

Each of the ball bearing assemblies 14 and 15 are supported on four symmetrically arranged flanges which are of course spaced about 90 apart. Thus the front ball bearing assembly 14 is supported on the four flanges 50. The rear assembly 15 is supported on similar flanges 51.

In order to provide a secure assembly of shaft 13 and rotor 17 and as an aid in maintaining them in axial alignment the shaft 13 adjacent the rotor 17 is provided with a transverse circular base flange 52 having a flat rear surface 53 that is at right angles to the longitudinal axis of the shaft 13 with this surface being received in a circular recess 54 on the side of the rotor forward wall that is adjacent the flange 52.

la the illustrated embodiment the forward end 55 of the shaft 13 extends beyond the forward ball bearing assembly 14 and is threaded to receive a tool holding collet (not shown) such as a small grinder wheel commonly used in grinding articles during a manufacturing step.

As shown in FIG. 3 the two fluid exits 22 and 23 where the fluid is ejected from the interior 18 of the rotor after exerting its pressure power on the inclined surfaces are free of any fluid compressing flow restrictions. Thus in the illustrated embodiment this is achieved by keeping these passages 22 and 23 as short as possible, by having each inner side wall 45 of the exit flat and substantially parallel to a tangent to the rotor and by having each outer side wall 46 a smooth extension of the rear end of the corresponding inclined surface 26 and 31. Thus the exiting fluid which has given up its pressure energy to rotation torque on the rotor is released from the interior 18 of the rotor as rapidly as possible and without imparting energy to the exiting fluid. As has been explained earlier, the airfoil leading ends 27 and 32 of the wall members and forming the surfaces 26 and 31 also contribute to the rapid venting of the fluid without substantially compressing the fluid on its way to and through the exits.

In the illustrated embodiment the rotor 17 has the forward wall 37 united with a rear wall 56 at the rear edge 57 of the fluid confining wall member 25. This of course provides the hollow interior 18 which functions as a part of a fluid conduit system to direct flowing fluid radially outwardly against the inclined surfaces 26 and 31 as previously described. If desired, however, the rear wall 56 could be separate from the forward wall 37 and fixed in position so that the rotating forward wall 37 would have a small clearance at the edge 57 with the rear wall 56. However, the illustrated construction is preferred.

Having described our invention as related to the embodiment shown in the accompanying drawings, it is our intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the appended claims.

We claim:

1. A pressure fluid engine comprising a rotor rotatable about a central axis, said rotor being hollow and bounded by a front and rear wall with a peripherally circular wall therebetween, said rotor having a central opening in one of said front and rear walls, said rotor having a smooth vaneless inner chamber portion adjacent said central opening and an outer vaned impelling portion, each of said vanes being of airfoil section having a substantially rounded leading edge, and an inner surface spiraling smoothly, arcuately outwardly and terminating in a trailing end lying in said peripheral circular wall, said adjacent vanes having cooperating relation and defining tangential substantially unrestricted discharge nozzles therebetween, each of saidvanes extending substantially about the axis of said rotor and projecting means defining a smooth outwardly extending flow surface from said other of said walls toward said central opening whereby fluid flow into the hollow rotor from said central opening is turned smoothly from an axial direction to radial in said vaneless portion of the rotor to enter said vaned portion with a radial component.

2. A pressure fluid engine comprising a rotor comprising a unitary plastic construction rotatable about. a central axis, said rotor being hollow and bounded by a front and rear wall with a peripherally circular wall therebetween, said rotor having a central opening in one of said front and rear walls, said rotor having a smooth vaneless inner chamber portion adjacent said central opening and an outer vaned impelling portion, each of said vanes being of airfoil section having a substantially rounded leading edge, and an inner surface spiraling smoothly, arcuately outwardly and terminating in a trailing end lying in said peripheral circular wall, said adjacent vanes having cooperating relation and defining tangential substantially unrestricted discharge nozzles therebetween, each of said vanes extending substantially 180 about the axis of said rotor and projecting means defining a smooth outwardly ex-' tending flow surface from said other of said walls toward said central opening whereby fluid flow into the hollow rotor from said central opening is turned smoothly from an axial direction to radial in said vanestantially rounded leading edge, and an inner surface spiraling smoothly, arcuately outwardly and terminating in a trailing end lying in said peripheral circular wall, said adjacent vanes having cooperating relation and defining tangential substantially unrestricted discharge nozzles therebetween, each of said vanes extending substantially about the axis of said rotor and projecting means defining a smooth outwardly extending flow surface from said other of said walls toward said central opening whereby fluid flow into the hollow rotor from said central opening is turned smoothly from an axial direction to radial in said vaneless portion of the rotor to enter said vaned portion with a radial component, each said airfoil section comprising an outer wall forming the aforesaid peripheral circular wall, the leading end portion of said airfoil outer wall being a flat extending surface and forming a part of one of said discharge nozzles. 

1. A pressure fluid engine comprising a rotor rotatable about a central axis, said rotor being hollow and bounded by a front and rear wall with a peripherally circular wall therebetween, said rotor having a central opening in one of said front and rear walls, said rotor having a smooth vaneless inner chamber portion adjacent said central opening and an outer vaned impElling portion, each of said vanes being of airfoil section having a substantially rounded leading edge, and an inner surface spiraling smoothly, arcuately outwardly and terminating in a trailing end lying in said peripheral circular wall, said adjacent vanes having cooperating relation and defining tangential substantially unrestricted discharge nozzles therebetween, each of said vanes extending substantially 180* about the axis of said rotor and projecting means defining a smooth outwardly extending flow surface from said other of said walls toward said central opening whereby fluid flow into the hollow rotor from said central opening is turned smoothly from an axial direction to radial in said vaneless portion of the rotor to enter said vaned portion with a radial component.
 2. A pressure fluid engine comprising a rotor comprising a unitary plastic construction rotatable about a central axis, said rotor being hollow and bounded by a front and rear wall with a peripherally circular wall therebetween, said rotor having a central opening in one of said front and rear walls, said rotor having a smooth vaneless inner chamber portion adjacent said central opening and an outer vaned impelling portion, each of said vanes being of airfoil section having a substantially rounded leading edge, and an inner surface spiraling smoothly, arcuately outwardly and terminating in a trailing end lying in said peripheral circular wall, said adjacent vanes having cooperating relation and defining tangential substantially unrestricted discharge nozzles therebetween, each of said vanes extending substantially 180* about the axis of said rotor and projecting means defining a smooth outwardly extending flow surface from said other of said walls toward said central opening whereby fluid flow into the hollow rotor from said central opening is turned smoothly from an axial direction to radial in said vaneless portion of the rotor to enter said vaned portion with a radial component.
 3. A pressure fluid engine comprising a rotor comprising a unitary plastic construction rotatable about a central axis, said rotor being hollow and bounded by a front and rear wall with a peripherally circular wall therebetween, said rotor having a central opening in one of said front and rear walls, said rotor having a smooth vaneless inner chamber portion adjacent said central opening and an outer vaned impelling portion, each of said vanes being of airfoil section having a substantially rounded leading edge, and an inner surface spiraling smoothly, arcuately outwardly and terminating in a trailing end lying in said peripheral circular wall, said adjacent vanes having cooperating relation and defining tangential substantially unrestricted discharge nozzles therebetween, each of said vanes extending substantially 180* about the axis of said rotor and projecting means defining a smooth outwardly extending flow surface from said other of said walls toward said central opening whereby fluid flow into the hollow rotor from said central opening is turned smoothly from an axial direction to radial in said vaneless portion of the rotor to enter said vaned portion with a radial component, each said airfoil section comprising an outer wall forming the aforesaid peripheral circular wall, the leading end portion of said airfoil outer wall being a flat extending surface and forming a part of one of said discharge nozzles. 